Light emitting diodes operate to release light photons as electrons transition between excited and resting states. In order to conventionally initiate the release of light photons, a sufficient voltage must be applied to the light emitting diodes, e.g. 1.2 volts. The present invention is directed to a construction for enabling light emitting diodes to emit light photons with a reduced applied voltage, using the characteristics of a tunnel diode.
Tunnel diodes are well known and are commonly utilized as a self-excited frequency down converter. One characteristic of a tunnel diode is its ability to be biased to a self-oscillating operating point. By proper sizing of the tunnel diode junction cross-section, a tunnel diode may be biased to self-oscillation, outputting a high frequency signal. Prior publications have disclosed constructing and biasing a tunnel diode circuit to output signals in the tunable FM frequency range, e.g. GE Tunnel Diode Manual, G.E., Syracuse, N.Y. (1961) and ABC's of Tunnel Diodes, Gallan, P., SAMS Catalog #TDK-1.
The present invention is directed to a modification of prior uses of a tunnel diode circuit to bias a tunnel diode to tunably self-oscillate in the visual frequency range. The tunnel diode output signal is then used to drive a light emitting diode. As a consequence of the frequency of the tunnel diode output signal the light emitting diode can be excited to emit photons, i.e. to emit light, by resonant pumping, without the need to apply conventional voltage levels to activate the light emitting diode, e.g. approximately 1.2 volts.